Conventional Storage Concepts Advanced Storage Concepts LNG Storage

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Historically, approximately 13% (3.1 Trillion cubic feet) of the natural gas consumed in the United States is delivered from storage facilities, primarily during the heating season from November to March. Natural gas is stored in two basic ways – compressed in tanks as liquefied natural gas (LNG) or in large underground storage facilities such as depleted gas wells, salt caverns, or rock caverns, abandoned mines, and aquifers. By far, the greatest volume of gas is stored by this second method, usually in depleted gas wells. Each year, from April to November, operators inject excess summer production into approximately 400 storage reservoirs across the country. Most of these facilities are located near major eastern and mid-continent markets. They account for almost 4 trillion cubic feet of storage capacity, or over 13% of one year’s national gas consumption. This storage system serves the market place in several ways. Most importantly, it allows consistent delivery of the natural gas resource to consumers. Second, it stabilizes supply by sustaining production levels in the summer and eliminating shortages in the winter. Third, it eliminates the need for expensive, additional pipeline transmission capacity that would be necessary to supply peak demand. Finally, it provides confidence in and encourages the use of an environmentally friendly, clean burning fossil fuel.

The use of natural gas is projected to increase at a rate of 1.4% per year for the next 2 decades. During this time, there will be a significant shift in consumption patterns as population centers change and more natural gas is utilized in the production of electricity to power summer air conditioning. Present storage wells must be renewed or replaced as older storage areas experience "wear" due to the yearly cycles of injection and extraction of gas.

In 2004, NETL's Natural Gas Delivery, Storage, and LNG Program in collaboration with Pennsylvania State University established the Natural Gas Storage Technology Consortium (GSTC) [external site]. The GSTC mission is to assist in the development, demonstration, and commercialization of advanced storage technologies. Currently, the membership includes 40 individual companies or organizations. The GSTC will be the cornerstone for future natural gas storage R&D efforts.

Liquid Hydrocarbon Storage
Storage of liquid fuels for large consumption is not as common as with natural gas. However, the Department of Energy does maintain one large crude oil storage facility, the Strategic Petroleum Reserve (SPR). The Strategic Petroleum Reserve (SPR) is the world's largest supply of emergency crude oil. The federally-owned oil stocks are stored in huge underground salt caverns along the coastline of the Gulf of Mexico. Decisions to withdraw crude oil from the SPR are made by the President under the authorities of the Energy Policy and Conservation Act. In the event of an energy emergency, SPR oil would be distributed by competitive sale. Although the SPR has been used for emergency purposes only once (during Operation Desert Storm in 1991), its formidable size (more than 600 million barrels) makes it a significant deterrent to oil import cutoffs and a key tool of foreign policy. The SPR is comprised of salt caverns. Since salt caverns are essentially impermeable, they are ideal for storing large quantities of high pressure hydrocarbons.

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